Question

Explain why most GSM operators evolved to UMTS as 3rd generation, and why Interim Standard 95 (IS-95) operators selected cdma2000 for their 3rd generation system.

Answer 1

Because the UMTS (Universal Mobile Telecommunications System) system, first offered in 2001, standardized by 3GPP, used primarily in Europe, Japan, China (however with a different radio interface) and other regions predominated by GSM (Global Systems for Mobile) 2G system infrastructure. The cell phones are typically UMTS and GSM hybrids. Several radio interfaces are offered, sharing the same infrastructure:

• The original and most widespread radio interface is called W-CDMA (Wideband Code Division Multiple Access).
• The TD-SCDMA radio interface was commercialized in 2009 and is only offered in China.
• The latest UMTS release, HSPA+, can provide peak data rates up to 56 Mbit/s in the downlink in theory (28 Mbit/s in existing services) and 22 Mbit/s in the uplink.
• the CDMA2000 system, first offered in 2002, standardized by 3GPP2, used especially in North America and South Korea, sharing infrastructure with the IS-95 2G standard. The cell phones are typically CDMA2000 and IS-95 hybrids. The latest release EVDO Rev B offers peak rates of 14.7 Mbit/s downstream.

And Interim Standard 95 (IS-95) operators selected cdma2000 for their 3rd generation system because CDMA2000 is an improvement on TIA/EIA IS-95. It provides a significant improvement in voice capacity and expanded data capability, and is backward-compatible with IS-95 handsets.

Code Division Multiple Access (CDMA) is a digital technique for sharing the frequency spectrum. Multiple users are assigned radio resources using spread Spectrum techniques. Although all users are transmitting in the same RF band, individual users are separated from each other via the use of orthogonal codes. CDMA is based on proven Spread Spectrum communications technology”

There are several CDMA implementations that are currently deployed or under development. The first commercial and most widely deployed CDMA implementation is cdmaOne.

CDMA is an advance digital technology that can offer 7 to 10 times the capacity of analog technologies and up to 6 times the capacity of digital technologies such as TDMA. The speech quality provided by the CDMA systems is far superior to any other digital technology particularly in difficult radio environments such as dense urban areas and mountainous regions. It provides the most cost effective solution for cellular operators.

CDMA Technology is constantly evolving to offer customers new advanced services. The mobile data speeds offered through CDMA phones are increasing and new voice codecs provide speech quality close to wire line. Internet access is now available through CDMA terminals. The CDMA systems and technology have been standardized under Interim standard-95 (IS-95 A&B).